Conventional portable electronic devices such as electronic memo device and electronic pocket device allow a user to freely input and store data, and to search for the stored data in a desired order. For example, when the stored data are data of phone book, it is possible to search for the data in order of Japanese kana syllabary, alphabetical order, etc.
Other methods for searching data are, for example, schedule data search, first letter search, and keyword search.
There is a device having a bookmark function for searching purposes. Japanese publication of unexamined patent application (Tokukaihei) No. 5-101038 discloses a word processor having such a bookmark function.
This device is a word processor provided with a bookmark function for adding a mark or memo to a created document, and a bookmark edit function for searching for a bookmark. This device achieves laborsaving in creating a document, and improves the accuracy of proofreading a document.
Besides, regarding display devices such as a document processor with a driving device for manipulating document information, Japanese publication of unexamined patent application (Tokukaihei) No. 6-231186 discloses a display device that displays a state showing a visually recognizable mark, for example, bookmark, for reference.
However, with the above-mentioned conventional structure, in a portable electronic device having a plurality of modes, when data marked with a bookmark is retrieved by the bookmark function, i.e., in a state in which a bookmark mode is selected, if the data is simply displayed, an operator cannot know a mode to which the data belongs. Therefore, the conventional structure is unsatisfactory in terms of the improvement of the facility of operations using the bookmark function.
Moreover, in the bookmark function, if the number of data marked with bookmarks increases, even when only data marked with bookmarks are searched, it is necessary to deal a large amount of data. Therefore, the primary merit of bookmark is lessened.
Furthermore, as to the methods of searching the bookmark data, there is a method in which bookmark data of a particular mode are sequentially searched, and then bookmark data of another mode are sequentially searched. When this method is employed, for example, bookmark data in data of a phone book 1 mode are searched in order of Japanese kana syllabary, and then bookmark data in data of a phone book 2 mode are searched in order of Japanese kana syllabary. Subsequently, bookmark data in data of a phone book 3 mode are searched in order of Japanese kana syllabary.
Such a searching method is inefficient because data having low priority order for sorting may be retrieved first and then data of higher priority order than the previously retrieved data may be retrieved from the next mode.
Besides, although above mentioned Japanese publication of unexamined patent application (Tokukaihei) No. 5-101038 discloses placing a bookmark, it does not mention outputting of a mode of the retrieved data and the number of bookmarks placed.
Moreover, the above-mentioned publication does not mention giving a warning at the time the number of bookmarks placed exceeds the upper limit, nor retrieving data marked with a bookmark according to a predetermined sorting rule.
Furthermore, although Japanese publication of unexamined patent application (Tokukaihei) No. 6-231186 discloses placing a bookmark, it does not teach a structure of marking each data with a bookmark for data search purposes.